1. Field of the Invention
The present invention relates generally to an illumination apparatus, and more particularly, to an apparatus for eliminating a ghost image generated by adjacently arranged point light sources.
2. The Prior Arts
Light emitting diodes (LED), facilitated by the improvement of related technologies, now have the advantages of lower power consumption, and longer lifespan, and thus have been widely used for illumination applications. LEDs are usually featured with a very small size. Therefore, the luminance offered by a single piece of LED is typically not comparable with an ordinary incandescent lamp, fluorescent lamp, or other conventional lamps. As such, an LED lamp used for illumination purpose is usually constituted of a plurality of LEDs. In such a way, the luminance provided by all of the LEDs can be gathered and concentrated for obtaining an applicable luminance.
When a plurality of LEDs are arranged in a certain area, the overall luminance obtained thereby can be equivalent to that of an ordinary lamp. However, an LED is substantially considered as a point light source, in which the center of the LED has the greatest luminance. In other words, the luminance of the LED is excessively concentrated. As such, when two or more such LEDs are adjacently distributed and concurrently used, a superimposed shadow which is also known as a ghost image often occurs. Working under such an illumination environment, eyes are likely to feel uncomfortable, or even dizzy.